Tbansmission-geab mechanism



Aug. 12, 1924. l 1,504,936

` T. "r, BURCHELVL THANSMISS ION GEAR MEGHANI SM Filed April 29. i924 5 Sheets-Sheet 1.

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1 N E w i "A TTORNEYY Aug. 12, 1924.

T. T. BURCHELL.

TRANSMISSION GEAR MECHANISM Filed Apil 29 1924 3 Sheets-Sheet 3 A 7 TORNE Y.

Patentedv Aug. 12, 1924.

UNITED STATES THEOPHILUS T. BURCHELL, DE MANCHESTER, KENTUCKY.

TRANSMISSION-GEAR MECHANISM.

Application filed April 29, 1924. Serial No. 709,808.

To all whom it may com-cm.'

Be it known that I, THEOPHILUS T. BUR- cHnLL, a citizen of the United States, re-

. siding at Manchester, in the county of Clay 45 and State of Kentucky, have invented certain new and useful Improvements in Transmission-Gear Mechanism, of which the following is a specification.

This invention relates to a transmission gear mechanism of the speed change type for motor vehicles, and has for its object to provide, in a manner as hereinafter set; forth, a mechanism of such class with means whereby the speed of the vehicle may be changed at will without varying that of the engine and without releasing the engine clutch, as well as providing for varying the speed of the vehicle without causing any noticeable shock.

A further object of the invention is to provide, in a manner as hereinafterset forth, a transmission ear mechanism of the s eed change type inuding means which wi l at all times exert power upon the driven shaft while going from a lower to a higher speed.

A further object of the invention is to provide a transmission mechanism of the speed change type, in a manner as hereinafter set forth and with means by shifting to neutral from low gear will answer the same purpose as the clutch now employed between the motor and a transmission. 4

Further objects of the invention are to provide, in a manner asV hereinafter set. forth, a transmission gear mechanism of the speed change type, which is simple in its construction and arrangement, strong, durable, compact, thorou h y eiicient and convenient in its use, read y assembled and comparatively inex ensive.

Wlith the foregoing and other objects in view, the invention consists of the novel construction, combination andA arran ement of parts, as hereinafter more speci cally described and illustrated in the accompanying drawings, wherein is shown an embodiment of the invention, but it is to be understood that changes, variations and modifications can be resorted to which come within the scope of the claims hereunto appended.

-In the drawings wherein like reference characters denote corresponding parts throughout the several views:-

Figure 1 is a section plan of a transmissiomgearmechanism in accordance with this mventlon Figure 2 .is a fragmentary view in longitudlnal section, illustrating the driven shaft of the transmission and the driving gear elements carried thereby.

Figure 3 is a vertical sectional view of one of the driving gear elements.

Figure 4 is a section on line 4--4, Figure 3.

Figure 5 is a section on line 5--5, Fi re 3.

Figure 6 is a pers ective View o a retainervcollar employe in connection with a driving gear element.

Figure 7 is a perspective view of the removable side plate of a drivin gear element.

Figure 8 is an end view of t e drum forming an element of a frictional clutch used in connection with each of the driving gear elements.

Figures 9 and 10 are yfront views of the different forms of friction rin em loyed in connection with each clutc ing evice.

Figure 11 is a perspective view, broken away, of the driven shaft of the transmission.

Figure 12 is a like view, broken away, of a modified form of driven shaft.

` Figure 13 is a fragmentary view, in section, of the form of driven shaft shown in Figure 12.

Figure 14 is a fragmentary view, in section, of one of the driven gear elements and its ratchet or clutching connecting with respect to the driving or propeller shaft.

Referring to the drawings in detail, 1 denotes a housing Vhaving extending therein, at one end thereof, the motor or engine shaft 2. That end of the housing through which extends the shaft is indicated at 3 and provided with a bearin 4 for the shaft 2. Bel w the bearing 4 t e end 3 of the housing l is formed with a bearing 5. The other e 1d of the housing is indicated' at 6 and is formed on its outer face with a bearing 7, arranged in alignment with the bearing 4 and below the bearin 7, the end 6 is formed with a bearing 8, w ich is arranged opposite the bearing 5.

Mounted in the bearings 5, 8, and extendinig through the chamber 9 formed by the housing 1, is a driven shaft 10, and loosely connected with that end of the shaft 2 within,the chamber 9 is the end 11 of a drivin or' propeller shaft 12 which extends throug the bearing 7. If the 12 is formed of `,two sections, e of the sections isprovided with a universal ioint connectien 13, so that one section will he connected to the other by the joint 13. Keyed to that end of the motor or engine shaft 2 extended within the chamber 10, is a gear wheel 14 which permanently meshes with a ar wheel 15 of the suine diameter and whic is keyed to the driven shaft 10. (ln the operation of the shaft 2, the gear 14 acting on the geur 15 will drive the shaft 10 and durin the operation of the shaft 2 the shaft 10 wiv be synchronously operntedtherewith.

The shaft 10 is formed from end to end with a lengthwise extending rectangular bore 16 which is open at each end. The bore 16 is also disposed diametrically with respect to the shaft 10, and the latter is furthermore provided with two series of spaced rectangular openings 17. The openings of each series at their inner ends communicate with the sides of the bore 16 and at their outer ends open at the periphery of the shaft 10. The number of openings of n series corresponds to the number of speed change driving gear elements carried by the shaft 1U. and by wey of example, the number of speed change driving gear elements illustrated is six, but it is obvious that this number can be increased or diminished if desired. The openings of one series align with the openings of the other series.

The shaft 10 has lts periphery formed with :i pnirof lengthwise extending frooves 18 which are diametrieally dispose with respect to euch other, extends from one end to the other `end of the shaft. and disposed ut right :mglcsto the openings 18.

Carried b v the shaft 10 is n reversing driving geur eleinent 20, of smaller diameter thun the geur 15, and slmft l0 is u peil' of forwardly drivin speed change geur driving elements 21 an 22 of the sume dimnctvr und of less diameter than the gen1' l5. :i pair of forwardly driving speed chungo gear driving elements 23, 24 oi' greater diumcter thun the gear 15 and elements 21` 22, ande forwardly driving .spoed change geur driving element of grenier diameter than the elements 23 and 2l. The elements 21 und 22 nre for low speed, elements 23. 24 for intermediate Speed, und clement 25 for high speed.

lloeh of the speed change gunrtdi'iving elements is of the sume construction, und, tiurcforc, but one will he described :is the description oic one will apply to euch of the other speed change geni driving elements.

"he construction of euch of the speed rlmnge geur drivingr elements is best shown in Figures 3 to l0. both inclusive, and each] ol' said elements consists of :i pair of spaced retaining collars 2H, 27, secured in position ty set screws 28 thrcudedly engaging with the collars :md further binding against the shaft 10s Openings 29. having threaded walls. ore provided for the screws 28.. The collar 2G is formed with n reduced annular also mounted upon theA extension 26' having its inner face formed with n pair of diametricully opposed lugs 30, which engage in the grooves 18 of the shaft 10. The outer face 31 of the extension 26' provides n bearing surface for a -purpose to e presently referred to. The set of clamping screws 28 for the collars 26 and 27 ma if desired have threaded engagement wi the shaft 10. A Q Each of said elements further includes u gear member consistin of. a circular web 32, having an opening g3 for the nrpose of mounting the web 32 upon the s luft 10. The web 32 is positioned against the collar 27. Integral with the outer portion of the web 32 and Vin section disposed at right angles with respect to the web 32, is an annulus 34 of substantial width and which has its outer face provided circumferentinlly throu hout with transversely extending space teeth 35. Integral with the inner face of thev nnnulus 34 is a series of transversely extending s aced lugs 36, and one end of euch of said is inset with respect to one edge of the annulus to provide n ledge 37 und a shoulder 38. The inset end of each lug 36 is formed with u socket 39, having u threaded wall.

Mounted upon the bearin surface 31 is a removable circular closure p ate 40, provided centrally with an opening 41 for mounti on the extension 26 of the collar 26. The plate 4() has a series of spaced openings 42 in proximity to its edge, and the said late 1s positioned against the .ledge 37 an the shoulder 38. The outer face of the plate 40 is flush with one edge of the annulus 34. The o enings 42 register with the sockets 39 un extending through said openings 42 und engaging the threaded walls of' the sockets 39 are countersunk hold-fast devices 43, for detuchably connecting the plate 40 to the annulus 34.

The ear member is loosely mounted on the shn t 10, and is adapted to be-coupled thereto so ns to revolve bodily therewith, and for this purpose n clutching device is employed consisting of a drum forined of an annuler body portion 44 und n pair of heads 45, 46, euch provided with nu opening 47 for mounting upon the shaft i0. The wel] of the opening 47, of ezich head, is cprovided with n pair of diametricully oppose lugs 48, which engage in the grooves 18 of the shaft 10, so that the drum will be carried at. all times with the shaft 10, or in other words,

the drinn revolves bodily with t e shaft 10.'

The body portion 44 of the rum is ar'- rnnfred between and fixedly secured to the heads 45, 46, as well as having its outer face flush with the edges of the heads 45, 46. The body portion 44 of the drum, is formed with two oir of slots and with one pair pposed with respect to the diuluctrien ly 0 other Ilm'. The slots of euch pair ure indiin alignm' ent with respect to the ms other pair and each of the slots portion 44. The s ots of one pair are of .each air is o a length materially less than hal the width of the body portion 44. n The outer face of the drum is formed with a lseries of s acedv ribs 49, which op ose the lugs .36, an said ribs 49 'are of t e same length as the width of the drum and certain of the lugs 49 are intersected by the slots 47, 48. Mounted on the body ortion 44, between the slots of each air. o slots is a pair of spaced shiftable c anlping` members 50, 51, which` are notched, as vat 52, for the reception of; the ribs 49, whereby said clamping members 50 and 51 will 'bodily rotate wit the drum. The clam ing members 50, 51 extend to the 1u 36, utare not in binding contact therewit Mounted on the lbody portion 44, of the drum, is a series of friction clutching rings 53, and each of which has its inner edge formed with a series of spaced notches 54 `for the reception of the ribs 49, whereby the ri 53 wil bodily revolve with the drum.

urrounding'the body portion 44 of the drum, is a series of frictional clutching rings 55, each having its outer edge formed with a series of notches 56, for the reception of the lugs 36, whereb said rings when in clutching sition wil provide for the revolving iof t e gear member bodily with the drum.

The rin 53 and 55 are. alternately disposed wit res ect to each her,v and the outer rings of t e series of r' gs 53 are positioned rgainst the clampi g members 50, 51. See igure 3. /il

Under normal conditions, the clamping 'members 50, 51 and clutching rings 53 and 54, are out of clutching engagement but wh n the clamping members 50, 51 are shi towards each other, the action of said clamping members uson the rings 53, 55, will be such as to bin said rings frictionally together, under such conditions clutching the gear member with the drum so that said gear member, drum and shaft 10 will bodily revolve. l Associated with the clutching devices lwithin the gear members, is a `pair of oppositely disposed spring controlledshfting mechanisms there or, and as each shifting mechanism of a pair is of the same construction, but one will be described, `as the descri tion of ione will apply to both.

` Each of t e shifting mechanisms consists of a circular disk 57, having fixed toits aiis as well asproiecting from each face thereof a pivpt 58 and upon the ends of said pivot 58 iapiv ,4 y moited a pair of oppdsitely wry `arms 59, 60, connected together by a coiled pullin" spring 6l. One end of the spring 6l. is ixedly secured, as at 62, to the outer. ortion of the arm 59, and the other end of t ie spring 6l is fixedly secured, as at 63, to the outer portion of the arm 60.

Secured to the. head 45, in proximity to each'slot 47, is an inwardly extending fulcrum member 64. Secured to the head 46, as well `as projecting inwardy therefrom and arranged 1n close proximity to each slot 48 is a fulcrum member 65.

Extendill through each slot 47, into the drum is as iting arm 66 for the clamping member 50;'4 Extending through each slot 48, .into the drum, is a shifting arm 67 for `the clam ing member 51. The outer por- 69 thereof. See Figure `5. The outer por- J tion 68 of each of said arms is provided with an opening near its inner end for mounting u n a fulcrum member. The outer portions 68 of the arms 66 are mounted on the fulcrum members 64, and the outer portions 68 of the arms 67 are mounted on the fulcrum members 65. The shifting larms are retained on the fulcrum members by cotter pins 70. See Fi re 5. The reduced inner portions 69 o the arms 66 arey ivotally connected, as at 71, to the outer en, s of the arms 59. The reduced inner portions 69 of the arm 67 are ivotally connected, as at 7 2, to the outer en s of the arms 60.

The disks 57 of each pair of shifting clevice's extends through a pair of openings 17 and normally pro ect within the bore 16 and in the path o 'acontroller bar, to be presently referred to. The disks 57 of the shifting mechanisms, whenvsaid mechanisms are. mounted to operative osition, shift away from each other and w en said mecha sms are released the springs 61 act to ve said mechanisms to moperative posion, as indicated in dotted lines, Figure 3.

en the pair of oppositely disposed shift ing devices is operated they act upon the clamping members 50, 51 to clamp the rings 53 and 55 together, whereby the said rings will set up a frictional c utching action, causing thereby the operation` of the gear member withthe drum and shaft 10.

Slidably mounted in the bore 16 of the shaft 10 is a controller bar 73, provided intermediate its ends with an enlar ement 74, having each end thereof bevelle as at 75, and with the bevelled ends oppositely disos'ed with respect to each other. The enargement 74 constitutes an actuating cam for the shifting mechanisms. The enlargement 7 4 has a snug sliding fit with the side walls of the bore 16, and the length of the enlargement 74 is such to engage two pair of shifting mechanisms,simultaneously, or in other words, to act upon a pair of forwardly nl one Linie. but Enot of n' length to engiige three. The enlrgenient 74 constitutes 9; double :Ming ram so tlm! when the br 73`is shifted in one direction, one end ofthe en-4 largement 74 will engage a pair ofV op )osed shifting mechanisms and snichronoiisll'y sie# tuzltwthem, andwhe the ar 73 is' shifted in the other direction, the other bevelle'd end ot' the enlargement 74 Wi'llcn'gage 'and s 'nchronously nctnute'a pilir'of vopposed*shifting mechanisms; i l 'l The controller bar 73 projectsfror one end of the shaft I10, ss well as frorgxthefbear' ingo. und is conneete/d to an operatingele- -driving speed cinihge geur driving lements mon-t fvtherefbr. L -4 i The revel-5mg speed change "gearl driving i element is arrng'ed between the gear 15 an the speed 4change ietween the' elements 20 und the .distfmiee :md 21 is greater than the distance betvventhe elements 21` and 22, betweei'l elen'ients22 :md 23. between elements' and '24, between elements Q4 hud 25. and between thege'nr 1'5l und the elenient 20, und that )oition oft-ho Imre of the shaft-l0 between the elements `20 und:2l. lsindicated at 76,Vr provides Wliit nm'y he termed a, nentrl spatie fm'fthe enwhich meshes with and is of materially *less- 25. The gear 74 is of less diameter than'the'v w y shaft 10 ns cam 74 olearsthe clutching mechlargement. or--donble notingr cfim'fj. filon the cani 714e. is in the spnbe 76; 'eaohlof'the speed change gear driving elements' is' disconnected from the sli-aft 10;@ f Keyed to the .drivin-g shaft 12f`rmd arranged in elimini-ent 'with the elementI 2t)t is dgcnr. 66" of greater diameter thanthe said elonxentfQO, and `interposed between Athe gear 66 andjthe element 20 is an idler pinion 675 oarried'bynshaft: 68', mounted in bearingsl 69"; The! pinion.- 67 inuonneotionwith the element 20 andgear 66 provides for reverse drive-of the shaft 12 from the shaft 10.

, Keyed, to the shaft 12 ris a. gear 70 `which meshes with and 'is 'of 'greater'diameter than snidelement 21. Loosely mountod'ron th shaft 127 is s gear 71',v which meshes wit and is offgrrnter diameter than the element g2., The geur 71' is-of tho"same dimeter s the geur V. Keyed 'to the shaft-'12 is a; gear 72'; whchimr-shes with and is of less diametri.:thun-the elemrnt 23.' f The geni'. T2' is of'loss tlnmeter than the dinmeterof the gem-'71. Loosely mounted on the'slmft 1-2 is n genrh'l. .which meshes with the. element- 24 `und is of the sme diameter n'srthe goor T9'. Keyed to the slmtt12fv is a gear 74 diameter than the diameter of 'theo-element.

gear 73. t

The gears 7l :md 73', as before stated, nre loose, on the slmft- 12 but `haveeooperotingr therewith n clutvh or ratchetdeviee for the seof connecting said gears; with the slin t l2. ily wn'v of exemple, the gears 71 und T3 mm bo svt up in the manner :is shown ing f O in Figure 14, :sind Yby reference thereto the shaft 12 has keyed vthereto a. clutehin "menif b'er 77, provided 'with a series of `g obular 7 8 engatgeabie Ywith acollar 79, osx-- ried by the gear or the purpose of clutching the letter to the shaft 12.

Inthe modified form ofvdriven shaft illusltrated 'in Figures 12 :ind 13, the shafntf'is in-` dioated atv81'and is formed with a, rectangular bore 81 'similar to the bore 16. The shaft Stlhns its eriphery provided with ya pair of 'dlame'tri'oa ly opposed iengthwiseextendn rooves 82 having the bottoms theres ormed with. openings 83 ini which are to be 'arranged thed'sks 57 of thel shiftin mech- `ensms. Thelditference between the s ett 80 and the shaft 1 0, is that the openings, 17 in the shaft 10 are disposed at right angles to theroove 18, whereas the openings 83 in the sha t 80 which corre' nd to the openings 17 are arranged at the ottom of the grooves 82, which correspond to lthe grooves 18 of Y the shagftll r' i As il'lnstrnted rind'described;Y the gear 14 is keyed'to Ythe shaft 2;"gear 15'to the shaft 10 and gems-66', 70', 72', and 74 to the shaft 121 yfIle-Jgenrs 70", 72 and 7 ea'ch provides d so id working gearifcase it Vis desired to" lknpioy the engine as a brake when slo'wlycoas 'ingidown hill; Gears 71'- "an'f' siro V'nmnhlly' loose on the shaft-.12, `butrtfther one can' be clutched therewith 'for' 'the' purposfe of s. 'plying power thereto. f Gear 71 is lutehe to the shaft 12whe'n driven from element 22 when the I ntte'is clutched to the shaft 10. Gear 73"v is clutohed t the shaft 12V when driien froinelement 24- whe'n the latter is ltched tothe shaft 10.

The gears 70 and 71 are ofthe same `diumetei and' of the sante ratio tolenjgnts 21,

22.* Ifh geas'l' and 71nro driven by the el 1 t `s 1, 2 simultaneously when operat- `low speed;l but. -durm the eed oban operationfrom Ylow to mterme inte s ee ear 71 is only operated, due to the act, t at element 21 is unclutohed from shaft 10 as cam 74 clears the clutching mech# :mism for element. 21 before it fclems the .'clugihi-ng .mechanism for eldment, 22; The goers 72 and 73 are of the somediainelur4 and-ofthe same ratio to elements 23 and 24. The gears 72 and73' are driven h the elementsfa'nd 2'4 simultaneously en 'operltin lat. intermediate speed, but uing'v the spee change operation'from'intermediateto Vhigh speed gear 73' is only operated, clue to thefact-.that element. 23 is nnciutohed rfrom anism -for element 23 before it clears the clutch mechanism for element 24. Geur 74' isdrlven from element 25 when driving athighspsed.`V l.

The clutching/gears 71 and 73' provide means to prevent the loss of power while going from a lower to a higher speed, or in other words, by the employment of the clutching gears and their associated driving elements power will be exerted at all times on the propeller shaft 12 while going from a lower to a higher speed.

It will be assumed that elements 21 and 22 are clutched to and driven from the shaft 10. and when so clutched gears and 7l' will be driven from the' elements 21 and 22 and the propeller shaft operated. Now in going from element 22 to element 23, to change speed. the cam 74 first clears the clutching leases the latter from the shaft l0, but owing to the length of the cam 74, element 22 is still in clutching engagement with shaft 10, whereby the gear 71' is driving shaft 12, due to the fact that gear 71 is in clutched driving engagement with the shaftl2 and will remain in suchgqosition until the' cam 74 has clutched elgsiynt`23 to shaft 10. At this time, shaft -12 wi l be operated at a greater speed, under such conditions roviding for the imclutchin'g of the gear 1 from the shaft 12 as the latter will outrun gear 71', necessarily unclutching therefrom, or in other words, gear 72 which is operated from the clutch element 23 will out-run gear 71', thereby unclutching the latter.' By this arrangement no loss in power or any noticeable shock is present w en going from lower to intermediate speed. A'simllar action is had when going from element 24 to 'element 25 with respect to the Agearsfa'' and 74.

The clutching gears 71 and 73' carry the shift without the-necessity of throwing out the clutch or slowing down of the engine, or inother wordt. the element 22 and gear 71 and the clement 24 and gear 73' provide a medium for the change from one speed to another to enable the shifting from a lower to a higher speed without throwing the engine `clutch or causing a jerk or jolt.

The cam 74 is never in neutral position from the time it. engages element 21 up to the time it engages element 25. The cam 74 never releases one gear until it engages ,anothen and under such Aconditions the clutching gears are absolutely necessary.

B v shifting the bar 73, the various driving elements are coupled to the shaft 10 so as to drive the associated gear. The element 20 is for reverse drive and to operate the same it requires the cam 74 to pass through the neutral space 75 before it engages the shifting devices within said elgment for the purpose of operating such device to clutch said element 20 to the shaft 10.

The operating means for the controller bar 73 may have any provision such as a lug or spring to prevent shifting from low speed to high speed too suddenly.

lt is thought that the many advantages of a. lspeed change gear driving mechanism,

mechanism for element 21 and re-v in accordance with this invention can he readily understood, and the preferred embodlment of the invention is as illustrated and described, yet changes in the details of construction can he had which will fall within the scope of the invention as claimed.

What I claim is:-

1. A transmission gear. mechanism comprising a driven shaft, meanioperated from the motor of the vehiclel for continuously operating said shaft during the operation of the motor, Ia. 'driving shaft, a plurality oftpalirs of speed. chan e gears mounted en said driving shaft, 'xe gears of each :pair being of the same diameter and one xed to and the other clutching' with said driving shaft, the rs ofl ione. pair,he mg of a different diameter with to the gears of the other pair, a plurai pairs of speed change driving elementi mounted in inactive position on sai ven shaft, said elements permanently meshing with said gears, the elements of each ir being of the same diameter and o a di erent diameter with respect tofthe elements of the other pair, each of said elements includmg means for clutching it in an active position on the driven shat, and apcam element mounted in the d 'ven shaft for selectively coupling synchro ously a plurality of said elements to said driven shaft.

2. A transmission/gear mechanism comprising a driven shaft, means operated from the motor of the vehicle for continuously operating said shaft during the operation of the motor, a driving shaft, a plurality of pairs of speed change gears mounted on said driving shaft, the gears of each pair being of the same diameter and one fixed to and the other clutching with said driving shaft. the gears of one pair beiner of a different diameter with respect to thegears of the other pair, a pluralitv of pairs of speed change driving elements mounted in in active position on said driven shaft. said element permanently meshing with said gears. the elements DI each pair being of the same diameter a d of a ditl'erent diameter with respect to the elements of the other pair, each of said elements including means for clutching itl in an active position on the driven shaft, a cam eieruent mounted in the driven shaft for selectively coupling synchronously a plurality of said elemente to said driven shaft. a. gaat carried hy the driving shaft, a pinion meshing therewith for reversing the drive thereof, and a` gear drive element normally inactive on said driven shaft and meshing with said pinion and including means operated from the cam element for clutching it in active position with respect to the driven shaft.

3. A transmission gear mechanism comprising a driven and a driving shaft, a plurality of pairs of speed change gears mounted on one of said shafts, the gears of each air being of the saine diameter and one gxed to and the other clutching with such shaft, the gears of one pair being of a different diameter with respect to the gears of the other pairs, a plurality of pairs of s eed chan e gear driving elements mounts in inactive position on the other of said shafts, said elements permanentl 7 meshing with said gears, the elements o each pair being of the same diameter and of a different diameter with res ect te the elements of the other pair, each of) said elements including means for clutching it in an active osition on its respective shaft, and a cam element mountv ed in that shaft carrying said elements for selectively coupling synchronously a plurality of said elements to their shaft.

4. A transmission ear mechanism comprising a driven shaft, a driving shaft, a pluralit of pairs of speed change gears mounted7 on said driving shaft, the gears of each pair beine of the same diameter and one ermanenily fixed to and the other -clutc ing with said driving shaft, the gears of one pair being of a differentI diameter with respect to the gears of the other pair, a plurality' of pairs of speed change gear driving elements mounted in inactive position on said driven shaft, said elements pern'mnently meshing with said gears, the elements of each pair being of the same diameter, the elements of one pair being of a different diameter with respect to the other pair, each of said elements including means for clutching it in an active position on the driven shaft, and a cam element mounted in the driven shaft for selectively coupling said elements to said driven shaft.

5. A transmission rear mechanism coniprising a driven sha t, a driving shaft, a pluraiit of pai-rs of speed change gears mountedY on said driving shaft, the gears of each pair being of the same diameter and one ermanently iixed to and the other chit ing with said driving shaft, the gears of one pair being of a different diameter with respect to the gears of the other pair, a plurality of pairs of speed change gear driving elements mounted in inactive position on said driven shaft, said elements permanently meshing with said gears, the elements `of each pair being of the saine diameter, the elements of' one pair being of a different diameter with respect to the other air, each of said elements including means or clutching itdn an active position en the driven shaft, and means mounted in the driven shaft and prvided with a cam element for synchronously con ling one pair of elements er an element ofp opposed pairs of elements to said driven shaft.

6. A transmission ear mechanism comprisin a driven shail, a driving shaft, a pair o s eed change ears Amounted on said driving s aft and of t e same diameter with respect to each other, one of said ars being ermanently ixed to and t e other clutc ing with said driving shaft, a s eed chan e ar ermanently fixed to said riving s a t an opposing and spaced from the gear clutching with the driving shaft, a pair of speed change gear driving elements `mounted in inactive position on said driven shaft and each of e same diameter and permanently meshing with. said pair of speed change gears, a speed change gear driving element mounted in inactive position on said driven shaft and permanently meshingk with said single s eed change gear, each o said elements inc udin means for clutchin it in an active rposition on the driven s aft, and means mounted in said driven shaft for chronously Acoupling said pair of speed c ange gear driving elements to said driven shaft and further for synchronously coupling one of the elements of said air and said single element to the driven shaft. s

In testimony whereof, I aiix my'signature hereto.

THEOPHILUS T. BURCHELL. 

